Let's say I'm processing MB of data, I'm lazily iterating over
the incoming lines storing data in an associative array. I don't
want to copy unless I have to.
Contrived example follows:
input file
----------
a,b,15
c,d,12
...
Efficient ingestion
-------------------
void main() {
size_t[string][string] indexed_map;
foreach(char[] line ; stdin.byLine) {
char[] a;
char[] b;
size_t value;
line.formattedRead!"%s,%s,%d"(a,b,value);
auto pA = a in indexed_map;
if(pA is null) {
pA = &(indexed_map[a.idup] = (size_t[string]).init);
}
auto pB = b in (*pA);
if(pB is null) {
pB = &((*pA)[b.idup] = size_t.init);
}
// Technically unneeded but let's say we have more than 2
dimensions.
(*pB) = value;
}
indexed_map.writeln;
}
I qualify this code as ugly but fast. Any idea on how to make
this less ugly? Is there something in Phobos to help?
